Detergent laundry bars



Dec. 2, 1969 A. E. AUSTIN ET AL 3,481,880

DETERGENT LAUNDRY BARS Original Filed Feb. 21 1966 2 Sheets-Sheet 1 Q 56 Q 26 n INVENTOR.

AMQRY EARL Ausrm CHARLES FREDERICK F\$C\-\ER I W W/W4 70 E) Dec. 2, 1969E. AUSTIN ET AL 3,481,880

DETERGENT LAUNDRY BARS Original Filed Feb. 21 1966 2 Sheets-Sheet 2INVENTOR.

AM 0 RY EARL AUST t N CHARLES FRI-022K F SCHE-Q United States Patent C)3,481,880 DETERGENT LAUNDRY BARS Amory Earl Austin, Colonia, and CharlesFrederick Fischer, Jersey City, N..l., assignors to Colgate-PalmoliveCompany, New York, N.Y., a corporation of Delaware Continuation ofapplication Ser. No. 529,087, Feb. 21, 1966. This application Nov. 12,1968, Ser. No. 796,253 Int. Cl. Clld 1/02 U.S. Cl. 252-138 11 ClaimsABSTRACT OF THE DISCLOSURE A process for making low density builtdetergent laundry bars in which a plastic blend of synthetic anionicdetergent, water-soluble, hydratable builder salt and water is passedcontinuously through a zone of intense shear in the presence of gas andthe gasified mass is continuously extruded as a bar. Hydration of thehydratable builder salt occurring after extrusion, and contributing to,the hardening to the gasified bar.

This application is a continuation of our copending application Ser. No.529,087, filed on Feb. 21, 1966.

The present invention relates to a process and apparatus adapted for thecontinuous manufacture of a laundry bar comprising an anionic syntheticdetergent and water-soluble inorganic builder salts and to the resultingproducts, as hereinafter described.

Within the last decade, commercial interest has developed in a laundrybar containing a minor amount of synthetic detergent and a substantialproportion of inorganic salts, particularly due to the commercialsuccess and substantial consumer acceptance from about 1957 of adetergent bar product known in the detergent field under the name ofLimpiol. This product was a mechanically worked, plodded detergent barwhich contained usually according to analysis about 25-30% sodium higheralkyl benzene sulfonate detergent, about 60-65% inorganic salts andabout ll2% water. The inorganic salt in the product was about 35-40%sodium bicarbonate and about 18-20% sodium tripolyphosphate primarily.It is understood that this product was made by a batch method whichusually involved (1) mixing liquid alkyl benzene sulfonic acid and waterwith the inorganic salts in powdered form in a standard heavy-duty mixerto form a uniform mixture whereby powdered carbonate and bicarbonate dryneutralized the sulfonic acid to form the sodium salt with the releaseof carbon dioxide and Water,

(2) the mixing was continued until complete neutralization was obtainedfrom the practical'standpoint and, (3) the resulting solid mixture wasthen fed to a soap plodder which further mechanically worked andcompressed the mixture, and then extruded it in the form of a continuousbar which was cut into cakes or bars for individual use. It was knownalso to commercially manufacture laundry bars by equipment consisting ofa tilting amalgamator for mixing organic detergent salt and inorganicsalts, a mill for further fine mixing as desired, and plodders to forman extruded bar, such as US. Patent 2,845,391. Other methods aredescribed in US. Patent 2,205,037 and 2,941,948 for example.Subsequently, similar processes have been proposed such as described inUS. Patent 3,178,370 wherein a fine spray of sulfonic acid is sprayedonto an agitated bed of inorganic salts including carbonate to effectpartial neutralization of the sulfonic acid with the release of carbondioxide, and thereafter the mixture is further mechanically worked tomake it more homogeneous and to complete the neutralization.

The detergent laundry bars produced in accordance with all theseprocesses have, because of their high con- 3,481,880 Patented Dec. 2, 1969 tent of builder salts, been quite dense, typicall having a densityof about 1.57 as compared with the density of a typical laundry soap barof about one. Detergent laundry bars of the same weight as the ordinarylaundry soap bars have been, therefore, of considerably smaller size,presenting a correspondingly smaller surface area for washing purposes.

In accordance with one aspect of our invention, we have developed aprocess for making detergent laundry bars of substantially lowerdensity, despite the fact that the bars contain a large amount ofbuilder salt, well in excess of the amount of synthetic anionicdetergent. A mixture of the detergent, said excess inorganic salt andWater are passed, in plastic state, continuously through a zone ofintense shear in the presence of gas to disperse the gas throughout theplastic mixture passing through said zone. Preferably the mixture isformed by feeding the finely divided builder salt continuously to a zonein which there is formed continuously a mixture of the salt, detergent,and water, a gas is continuously dispersed into the material beingintensively sheared, and an intimate heated plastic blend of saiddetergent, said gas and said builder salt is continuously discharged.

In a highly advantageous and preferred embodiment, this gas-containingplastic fiowable blend is extruded directly as a bar through anextrusion opening of suitable size (large enough to form the bar), thefiowable plastic blend being maintained continuously in a heatedfiowable condition and continuously under shearing forces from the timeof its formation until its passage through the extrusion opening. Themechanically applied pressure used for the extrusion is advantageouslycomparatively low (e.g. well below about p.s.i.g.). Advantageously, theresidence time of the material in its travel from the intensive shearingzone to the extrusion opening is very short (e.g. well below 2 minutesand preferably less than 1 minute); the total residence time frominitial solid-liquid contact to extrusion is also advantageously veryshort, generally well below 10 minutes, and preferably less than 5minutes.

Individual laundry bars may be produced from the heated extruded porousmaterial by hardening the extruded bar (as by cooling at roomtemperature) and then cutting it to a suitable size. The cutting may beeffected prior to hardening.

By utilizing the process of this invention, bars of uniform texturehaving specific gravities well below 1.5, e.g., in the range of about1.1-1.4, and having a microscopic pores invisible to the naked eye,distributed throughout the thickness and Width of the bar, have beenformed continuously at high rates of production, without using heavyexpensive equipment and without the expenditure of a large amount ofenergy for the extrusion operation.

The water soluble anionic organic synthetic detergents which may bepresent in the compositions produced in accordance with this inventioncontain a sulfo acid solubilizing group joined (directly or indirectlythrough an intermediate linkage) to a hydrophobic organic group. Thus,such detergents include both organic sulfonates, e.g. RSO compounds andorganic sulfates, e.g. R-O-SO compounds, having sufficient watersolubility to form detersive aqueous solutions with foaming propertiesin concentrations which are suitable for use in laundering operations.In the formula, R is a radical having an aliphatic chain of at least sixcarbons, the radical preferably having about 8-30 carbons. Thedetergents may be used individually or in any desired combination.

Among the suitable water soluble anionic sulfonated detergents, thehigher alkyl aryl sulfonate detergents having about 8 to 15 carbon atomsin the alkyl group are particularly effective. It is preferred to usethe higher alkyl benzene sulfonate detergents for optimum eifects,

though other detergents containing a mononuclear aryl group, such asxylene, toluene or phenol, may be used also. The higher alkylsubstituent on the aromatic nucleus may be branched or straight-chainedin structure. Examples of straight chain alkyl groups are n-decyl,ndodecyl and n-tetradecyl groups derived from natural fatty acids andpetroleum. Examples of branched chain alkyl derivatives are propyleneand butylene polymers such as propylene trimer, tetramer and pentamer.Examples of other suitable water soluble anionic sulfonated detergentswhich may be satisfactorily used in the compositions of this inventionare the alkane sulfonates containing about 8 to 20 carbon atoms in thealkyl group and the alkyl sulfonates wherein the alkyl group of about 8to 20 carbon atoms is linked to the sulfonic acid group through a -COORgroup, e.g. oleic acid isethionate, -CONHR group, e.g. lauric acidtaurate, or a OR group, e.g. dodecyl glyceryl ether sulfonate, whereinthe R is a lower alkyl or a substituted lower alkyl group containing 2-3carbon atoms.

Among the suitable water soluble organic sulfated detergents which it ispreferred to use in compositions of the invention are alkyl sulfates,e.g. sodium lauryl or coconut fatty alcohol sulfate, and the alkylethyleneoxy ether sulfates, e.g. sodium lauryl tri-ethyleneoxy sulfate,said alkyl groups having about 8 to 20 carbon atoms and the ethyleneoxysulfates containing about 1 to 15, preferably 2 to moles of ethyleneoxide. The alkyl groups may be derived from naturally occurringglycerides or synthetically from petroleum, e.g. cracked waxes orethylene polymerization.

Other suitable organic sulfate detergents include sulfuric acid estersof polyhydric alcohols incompletely esterified with higher fatty acids,e.g. coconut oil monoglyceride monosulfate, and sulfated higher alkylphenolethylene oxide condensates having an average of about 2 to 18moles of ethylene oxide per phenol group and about 6 to 10 carbons inthe alkyl group. The sulfated higher alkyl phenol-ethylene oxidecondensates which it is preferred to employ have about 4 to 6 moles ofethylene oxide per phenol group and about 8 to 12 carbon atoms in thealkyl group.

In one preferred form of the invention, these sulfate and sulfonatedetergents advantageously are supplied to the shearing zone in an acidliquid state and are present in the final product in the form of theiralkali metal or alkaline earth metal salts. The preferred alkali metalsare sodium and potassium and the preferred alkaline earth metals arecalcium and magnesium. Optimum effects are obtained with the sodiumsalts in general.

The proportion of anionic organic detergent should be suitably selectedso as to yield a product having the desired performance and physicalcharacteristics. The detergent active functions as a foaming andcleansing agent as well as a plasticizer in the compositions of theinvention. The proportion of said detergent will be minor compared tothe inorganic salts, usually in the range of about 10 to 40% by weight,and preferably about 15 to by weight, of the finished bar.

The water soluble inorganic builder salts are known in the artgenerally. Particularly suitable are alkali metal or alkaline earthmetal salts, or combinations thereof. Ammonium or an ethanolammoniumsalt in a suitable amount may be added also, but generally the sodiumand potassium salts or similar salts effective to add hardness orstrength to the bar are preferred. Examples are the water soluble sodiumand potassium phosphates, silicates, carbonates, bicarbonates, borates,sulfates and chlorides. The builder salts contribute detersiveefiiciency when used in combination with sulfonic acid and/or sulfuricester organic synthetic detergents. Particularly preferred builder saltsare the alkaline builder salts such as polyphosphates, silicates,borates, etc. Inasmuch as the builder effects and processingcharacteristics of the individual salts vary to some extent, generallymixtures of inorganic builder salts are used in variable, predominating,proportions, e.g. about 45-85% by Weight of the finished bar, usually inthe range of about -75% preferably in proportion of about 50-65% byweight.

In the Water soluble inorganic builder salt mixtures used in thedetergent laundry bar compositions, it is preferred to have present amixture of sodium tripolyphosphate and sodium or potassium bicarbonate.The combination or mixture of salts wherein the bicarbonate totripolyphosphate ratio is selected from the range of about 1:1 to about3:1, and which when admixed with the particular organic detergent andWater in proportions such that this mixture of inorganic salts is atleast about 40% of the total weight of the manufactured bar, results indesired processing effects and produces bars having superior physicalcharacteristics. Preferably, the proportion of this particular inorganicsalt mixture is within the range of about 45 to about by weight of themanufactured bar.

Both Phase I and Phase 11 sodium tripolyphosphate and mixtures thereofmay be successfully used in the compositions. The usual commercialtripolyphosphate consists mainly of the Phase II material. Thecommercial tripolyphosphate material is usually essentiallytripolyphosphate, e.g. 87-95%, with small amounts, e.g. 4-13% of otherphosphates, e.g. pyrophosphate and orthophosphate. Sodiumtripolyphosphate in its hydrated form may be used also. While trisodiumorthophosphate may be used in the amounts indicated, its presence oftenresults in a bar which tends to sweat in hot, humid climates and whosesurface tends to slough off more readily in such climates.

The sodium or potassium bicarbonate is an effective pH buffer and ispreferred because the particular tripolyphosphate-bicarbonate mixtureresults in plastic detergent compositions which yield superior extrudedbars. This material is also desirable in that it is relativelyinexpensive, has suitable solubility and does not cause frosting on thesurface of the bar. The sodium bicarbonate may be incorporated directlyas anhydrous bicarbonate or in the form of sesquicarbonate, a hydratecontaining both bicarbonate and carbonate.

Other suitable builder salts which may be incorporated in the builtsynthetic detergent bar compositions include the water soluble sodiumand potassium silicates, carbonates, borates, e.g. sodium tetraborate,chlorides and sulfates, e.g. magnesium sulfate. Generally, the totalproportion of these additional builder salts will be within the range offrom 0.5 to 24% by weight of the manufactured bar. The sodium andpotassium silicates having an Na O:SiO ratio within the range of 1:1 toabout 3.5 :1 are particularly effective as corrosion inhibitors inproportions of about 1 to 8% by weight of the fiinished bar. The sodiumsulfate content is advantageously kept low, e.g. below /3 the weight ofthe phosphate (on an anhydrous basis); preferably, to avoiding frosting,the sodium sulfate content is below about 5% of the weight of the bar.

The final essential ingredient in the built synthetic detergent barcomposition is water or similar material. This component is generallypresent in a proportion within the range of about 2 to 30% by weight ofthe bar. This material serves as a plasticizer in the solid compositionsproduced by this invention and also helps promote the neutralizationreaction. It will be appreciated that the total amount of water is thesum of the amount added with the other ingredients in the feed (e.g. inthe sulfonic acid, or with the salts, or separately) and the amountformed during the neutralization reaction. It is preferred that thewater be from about 4% to 25% by weight.

The neutralizing agent may be contained, in solid form, in the mixedpowder fed to the intensive shearing zone, and the feed Water may besupplied in the liquid sulfonic acid portion of the feed. With certaindetergent acids (such as long chain alkylbenzene sulfonic acids) thepresence of the desired quantity of feed water causes partial gelationof the sulfonic acid-water blend, so that there are difficulties inmetering the blend accurately to the intensive shearing apparatus. Inthe practice of our invention we have been able to avoid this difficultyby adding the feed water continuously in a separate stream;advantageously, when the powder contains an ingredient (e.g. unhydratedsodium tripolyphosphate) which tends to form hydrated crystals oncontact with water, this separate stream of feed water is introducedinto the intensive shearing apparatus downstream of the point where theliquid detergent acid is fed, so as to allow intimate prior contactbetween the acid and the unhydrated material. Preferably this additionis made just slightly downstream of the point of contact of the acid andpowder, so that the moving builder salts come into contact with thewater within a few seconds after their contact with the acid. Ourinvention also makes it possible to use a liquid neutralizing agent andto employ alkali metal hydroxides as the neutralizing agents. Thus, anaqueous solution of sodium hydroxide (e.g. of about 20 to 75%concentration) may be used as the neutralizing agent, alone, or inconjunction with a solid neutralizing agent. It is advantageous to addthe stream of aqueous alkali metal hydroxide at a stage upstream of thepoint where the liquid detergent acid is introduced, particularly whenthe builder salt mixture contains material (such as solid carbonate and/or bicarbonate) which can act as a neutralizing agent; such upstreamaddition insures that the detergent acid will react preferentially withthe alkali metal hydroxide instead of with the carbonate or bicarbonate,even though the moving builder salts come into contact with the addedalkali within a few second prior to the time the mixture comes intocontact with the acid. Highly alkaline silicates such as alkaline sodiumsilicate may also be used as neutralizing agents, advantageously asaqueous solutions added in the same manner as the sodium hydroxide.

Optionally, a fatty acid alkylolamide may be included in the compositionof this invention. Such materials are generally condensation products ofhigher fatty acids having about 10l8, preferably 1014, carbon atoms inthe acyl group with alkylolamines selected from the group consisting ofmonoethanolamine, diethanolamine and isopropanol-amine. Examples arelauric, capric, myristic and coconut monoethanolamide, diethanolamideand isopropanolamide and the ethylene oxide adducts of such amides,(advantageously with small amounts, e.g. 1 to 2 moles, of ethylene oxideper mole of amide). The alkylolamides, which often act as suds builders,may be present in proportions within the range of about to 5%,preferably about 2%.

Various other ingredients may be included if desired, The compositionsmay beneficially include specific chelating agents capable of complexingiron such as the water soluble salts of ethylene diamine tetraaceticacid and the like. Other conventional auxiliary materials which may beincorporated in the compositions are soil-suspending agents such assodium carboxymethylcellulose, tarnish inhibitors such as melamine,fluorescent brightening agents, perfumes, coloring agents, germicides orbacteriostats, other detergent materials such as water-solublenon-ionic, amphoteric and cationic surfactants or watersoluble andinsoluble soaps, skin-conditioning agents such as glycerine or lanoline,and the like. These materials may be admixed with the compositions inany suitable manner which does not substantially adversely affect theplasticity of the compositions, and are preferably present in minoramounts relative to the synthetic anionic detergents.

Other ingredients which may be employed are starches (such as tapiocaflour, cornstarch, yucca starch or potato starch); the presence of thestarch aids in the processing of the mixture, improves its workabilityand appears to promote its flow over the inner walls of the bar-formingdie of the plodder. Other agents which have related effects, and whichmay be added together with or in place of the starch, are clays such asbentonite and kaolin, which like starch tend to absorb moisture andswell to form gels in hot aqueous media, zinc oxide and finely dividedcellulose (Solka-Floc), These additives may be included in amounts up toabout 20%; their effects are marked above about 5% (e.g. 7%); apreferred proportion is about 1()12% of starch. Starch also helps togive the bar a brighter color.

Another processing aid is a wax such as paraffin, which may be added asfine flakes mixed with the builder salts or dissolved or dispersed inheated detergent sulfonic acid. Related waxy materials such aspetrolatum may also be used. The wax also helps to increase the life ofthe bar in ordinary use and to prevent sweating of the bar in certainclimates, when used in small amounts (e.g. A1 to l%%); smaller andlarger amounts may be used as desired.

Among the particular detergent acid materials which may be used in theprocess are the industrially available alkyl aryl sulfonic acids havingan average molecular weight in the range of about 270 to 380, preferablyfrom about 300 to 380, prepared by sulfonating the corresponding alkylaryl hydrocarbon with a sulfonating agent such as sulfur trioxide, oleumor sulfuric acid to yield a liquid composition containing about 65-99%sulfonic acid, about 1-34% sulfuric acid or sulfur trioxide monohydrate,O.52% sulfonation by-products and about 0.10% Water.

The neutralizing agent used in the process (advantageously alkali metal,preferably sodium or potassium, carbonate, oxide or hydroxide) may, asindicated previously, be employed in solid hydrated or unhydrated form,e.g. as dry finely divided particles pre-mixed with the inorganicbuilder salt, or they may be supplied as aqueous solutions or slurries.The carbonates and bicarbonates generally are used in solid form.Advantageously there is present an amount of neutralizing agent at leastequal to the amount stoichrimetrically necessary for completeneutralization of the detergent acid and any acid constituents (such assulfuric acid) accompanying the detergent acid.

When the neutralizing agent is a suitable carbonate or bicarbonate, theinorganic builder salt may comprise only the neutralizing salt itself,in which case the neutralizing salt is usually present in excess of thestoichriometric quantity needed to completely neutralize the liquidorganic sulfo acid containing material. For best results, however,additional inorganic builder salts (e.g. polyphosphates) should also bepresent with the particulate neutralizing agent to enhance theperformance characteristics of the built detergent product. It is foundthat when excess unreacted soda ash is present in the final bar, theproduct is less advantageous in that it is not as smooth or as free frombloom.

The amount of Water (including water of neutralization) present in theintensive shearing zone will generally be varied in accordance with thetype and amount of anionic detergent formed therein. It should, however,be sufiicient to impart some plasticity to the anionic detergent at thetemperature of the shearing operation. Ordinarily, it is advantageous tosupply some water in addition to the water of neutralization. The amountof water present is such that the composition is plastic without theneed for an intermediate drying step. Water present in salt hydrateswhich are stable under the conditions prevailing in the shearing zonewill generally not be available for plasticiza= tion.

The heat liberated by the neutralization reaction raises the temperatureof the mixture of builder salt and anionic detergent and makes themixture more plastic and workable in the intensive shearing zone. Thetemperature attained in this zone will naturally depend also on theamounts and heat capacities of the builder salt and other ingredientspresent, as well as the amount of heat generated by the shearing. Insome cases it is advantageous to abstract some of the heat from themixture, as by circulating cooling fluid around the shearing zone. Theevaporation occasioned by the injection of the gas into the mixture mayalso have a cooling effect. It has been found, however, that the processmay operate over a wide range of temperatures of the material beingextruded from the intensive shearing zone; for example, temperatures inthe range of about 100 to 200 F.

As previously mentioned, the neutralization reaction takes place veryrapidly in the zone of intense shearing. In a preferred form of theinvention, the material emerging from that zone is practicallycompletely neutralized as evidenced by an indicator incorporation test.A satisfactory test for determination of the completion of theneutralization from the practical standpoint is by the incorporation ofa suitable dye as an indicator which normally changes color at a pH ofabout 3 to 4 in water, such as Pylaklor Detergent Blue S5OO orBromphenol blue. For example, the Pylaklor dye preferably dissolved inwater is added at a suitable inlet in a concentration of about 0.01% ofthe finished formula weight (for example, with an amount of watercorresponding to about 12% of the finished formula weight) with theinorganic salts and sulfonic acid. Where the mixture being discharged isessentially pink in color to the eye, then insufiicient neutralizationhas occurred, whereas a non-pinkish color, e.g. bluish, means that theneutralization is practically complete.

The gas used in the process is preferably air, which is 9 obviously thecheapest and most available. It is, however, within the broad scope ofthis invention to employ other gases such as nitrogen, carbon dioxide,etc.

The process does not require high gas injection pressures. A significantdecrease in the density of the product has been attained even when thegas pressure at the point of injection was only slightly aboveatmospheric. Pressures well below 100 p.s.i.g., e.g. on the order ofabout 20 to 60 p.s.i.g., have given excellent results.

The gasification treatment has been found to produce an intimateextrudable blend which flows readily at low mechanically appliedpressures but still retains its shape on extrusion.

Apparatus suitable for carrying out the process of this invention isillustrated in the accompanying drawings in which:

FIGURE 1 is a side view of the apparatus;

FIGURE 2 is a plan view with parts in cross-section;

FIGURES 3-6 are end views showing different positions of the paddlesused for mixing and intensive shears;

FIGURE 7 is an end view of one type of paddle, which acts also toadvance the material along the apparatus;

FIGURE 8 is a top view of the tip section of the paddle of FIG. 7;

FIGURE 9 is an end view showing one arrangement of the paddles;

FIGURE 10 is a side view, with parts in cross-section, showing anotherarrangement for discharging the material in the form of a bar or slab;

FIGURE 11 is a view of an end wall shown in FIG. 10, looking downstream;

FIGURE 12 is a side view, partly in cross-section, showing still anotherextrusion arrangement;

FIGURE 13 is an end view of the end wall shown in FIG. 12; and

FIGURE 14 is an overall schematic view showing one operating sequence.

The apparatus includes a jacketed housing 11 within which there aremounted a pair of parallel rotatable shafts 12 (FIG. 2), each extendinghorizontally the full length of the housing and each having mountedthereon, for rotation therewith, feed screw elements 13 and agitatorelements or paddles 14. The longitudinal cavity within the housing ismade up of two intersecting circular cylindrical zones (as can be seenfrom the end view in FIG. 3) meeting at upper and lower ridges 16 and17, respectively, each such cylindrical zone being coaxial with therotatable shaft situated in said zone, there being a small radialclearance between the inner walls of the cavity and the outerperipheries of the paddles and feed screw elements. There is an openingor hopper 18 at end of the housing, above the feed screw elements and aplurality of spaced injection ports 19, 21, 22 and 23 communicating withthe lower portion of the cavity.

The two shafts are adapted to be driven in the same direction by a drivemotor and gear arrangement 26 situated at one end of the housing. Thefeed screw elements on the shafts are of conventional helical type,suitably intermeshing in well-known fashion as the shafts rotate toadvance the material, supplied through the hopper 18, in an axialdirection towards the paddles.

The paddles 14 are arranged in matching pairs, the design being suchthat a tip 27 (FIG. 3) of one paddle of each pair is always moving inwiping relationship to an edge or flank 28 of the other paddle of thepair during the continuous co-rotation of the shafts. In theconstruction shown, the paddles of any pair are identical with eachother and mounted with their long axes LA (FIG. 4) at right angles, theedges 28 of each paddle being defined by equiradial symmetrical arcswhose centers are symmetrically situated on the prolongations of theshort axis SA of the paddle. As will be seen from the sequence shown inFIGS. 3 to 6, during the co-rotation of the shafts about theirrotational axes RA, one tip 27 of the left hand paddle follows along anedge 28 of the right hand paddle, two tips of the paddles then meet,after which a tip of the right hand paddle follows along an edge of theleft hand paddle. Thus, in a full 360 rotation, each edge of each paddlewill be wiped once by a tip of its matching paddle. During this full 360rotation, the internal walls of the housing 11 will be wiped twice bythe tips of the paddles.

Certain paddles are designed to advance the material longitudinally ofthe shafts. In these paddles (hereinafter called advancing paddles), theprofile of the rear face 31 (FIGS. 7 and 8) of the paddle 14 is offsetby a slight angle a (about the axis of rotation) from the profile of itsfront face 32. For example, for a paddle having its long axis 4% incheslong and its short axis 2 inches long, and having a thickness of 1 inch,the two faces may be offset by an angle of l2 /2. The other paddle ofthe same pair has the profiles of its faces similarly offset by theidentical angle, the design being such that the edge of flank of eachpaddle will be wiped by the tip of its paired paddle, as previouslydescribed. Thus, in any cross-section, through the pair of paddles, atright angles to the axis of rotation, the relationship of thecross-sectional profiles will be the same as that shown in FIGS. 3 to 6.To advance the material from the hopper end of the housing toward itsopposite end, the profile at the rear face of the paddle (that is theface nearest the hopper end) is preferably offset (from the profile atits front face) in the same direction as the direction of rotation ofthe paddles illustrated by the arrows in FIG. 7. It will be appreciatedthat while the tips are shown as being relatively sharp in the drawings,they may be relatively blunt, as indicated by the dotted lines on FIG.7, the dimensions being adjusted so that the tips, though blunt, stillare in close wiping relationship with the inner walls of the housing andwith the edges of the matching paddle.

To continue the longitudinal advance of the material, in a more or lesshelical path, the long axes of each successive pair of paddles may beoffset, by an acute angle, from the long axes of the pair previouslyengaged by the material being treated. FIG. 9 (in which the arrowsindicate the direction of rotation of the shafts) illustrates variouspositions of the front faces of successive paddles, the paddledesignated as I being nearer to the discharge end of the machine thanthe other paddles; the paddle II being next, then the paddle III andthen the paddle IV which is furthest from the discharge end, there beinga 45 angle between the long axes of successive paddles. This offsettingof the long axes of adjacent paddles also aids in the mixing action ofthe apparatus. As will be seen from FIG. 9, when the paddles are in theposition designated as II, for example, their further movement acts tocompress the material between the edges or flanks of the paddles and thewalls of the housing, forcing the material into the paths of themovement of adjacent pairs of paddles.

The front and rear faces 32, 31 of the paddles are advantageously flatand, when the paddles are mounted on the shafts and situated in planesperpendicular to said shafts, the faces of adjacent paddles arepreferably close to each other; thus the clearance between the frontface of one paddle and the rear face of the next paddle may be on theorder of about 0.03 inch. The clearances between the tips of the paddlesand the inner walls of the housing may be, for example, about 0.03-0.04inch; the clearances between the tip of the paddles and the edges of thepaired paddles which they wipe may be about the same, eg about 0.03inch.

At the discharge end of the apparatus, several arrangements may beemployed for extruding the material. In one arrangement (illustrated inFIGS. 10 and 11) there is an adjustably mounted end wall 35 having arearwardly projecting skirt 36 dimensioned to fit closely within thewalls of the housing 11, whose shape at this point is a symmetrical oval(formed by two spaced opposed vertical semicircles, of the same diameterand aligned with the corresponding inner walls of the main cavity in thehousing, joined by tangent horizontal lines). The material leaving thelast paddles 14 flows between the lower wall 37 of the housing and thebottom portion 38 of the end Wall 35. The skirt prevents flow of thematerial out of the sides and top of the discharge end. Smooth outwardflow is aided by the presence of an inclined apron 39 extending downwardfrom the lower wall 37.

In another extrusion arrangement, illustrated in FIG. 2, there is afixed end wall 41 completely blocking the end of the housing 11 (andhaving circular openings to closely receive the shafts) and arectangular horizontal discharge tube 42 leading from the space adjacentthe last group of paddles. With this arrangement, particularly goodresults have been obtained when successive paddles nearest the dischargeend have their long axes offset at a relatively large angle (preferablyat the maximum, 90, angle), as illustrated in FIG. 2 in which thesequence of the last five pairs of paddles is I, III, I, III, I (usingthe terminology discussed above and illustrated in FIG. 9).

In still another extrusion arrangement, shown in FIGS. 12 and 13, thereis a fixed end wall 44 having a rectangular bar-sized discharge opening45 therein, but otherwise completely blocking the end of the housing,the discharge opening being eccentrically arranged with respect to thecenter line of the cavity in the housing and located nearer to that sideof the housing which corresponds to the side where the motion of thepaddle tips has a generally upward, rather than downward, component.

In the operating sequence shown in FIG. 14, the extruded bar 51continuously leaving the discharge tube 42 is taken up on a movingendless belt 52, cooled and aged to harden it, passed through aconventional cutting device 53 and then stamped at 54.

Cooling water or other cooling or heating fluid may be passed throughany desired portion of the jacket 56 of housing 11.

In the use of the illustrated apparatus, best results have thus far beenobtained when the speed of rotation is such that there are about7000-11000 paddle cuts per minute; (a paddle cut occurs between thepaddles of successive pairs each time the paddle of one pair, on oneshaft, passes in close shearing relationship with a paddle of the otherpair, on the other shaft; for example, in FIG. 9 paddle I on the lefthand shaft and paddle II on the right hand shaft are just beginning tomake a cut. With all the pairs of paddles offset as shown in FIG. 9 ofthe drawing, there will be two cuts per full rotation; for example, with26 pairs of paddles [of 5-inch length], using a preferred speed of 175rpm, there will be 26 175 2:9,000 paddle cuts per minute).

Typically, the extrusion opening may have an area of at least 2 squareinches and a height (at least equivalent to the thickness of theindividual bars) in the range of about to 3 inches, and a width of atleast about 2 inches. The width of the extrusion opening may be equal tothe width of a single bar, or may be a multiple of that width, in whichcase the extrudate may be cut lengthwise before or after it is fullycooled and hardened (e.g. by pulling or pushing it past one or morecutting elements, such as thin vertical wires which may be heated tofacilitate the cutting).

The preferred extrusion temepratures are above F. One suitable range isabout 140 F.; the periphery of the extrusion opening may be heated to atemperature above (e.g. 1020 F. above) that of the extrudate to promotethe extrusion. It has been found, however, that much higher extrusiontemperatures may be employed, yielding special effects. Thus, in runsinvolving continuous neutralization (an exothermic reaction which tendsto heat the product considerably, as previously noted) there wasproduced an extrudate having a temperature above F. (e.g. 186 F.) whichextruded smoothly, as a bar, from the discharge opening, retaining thecrosssection of that opening (in this case, a side discharge tube suchas that shown at 42, rectangular in cross-section). The extrudedmaterial at this relatively high temperature was found to beconsiderably tougher and stronger than similar extrudates at lowertemperatures.

In a preferred form of the invention, the process is operated in suchfashion that the material being fed to the intensive shearing zone formsa plug capable of retaining the gas injected into that zone andsubstantially preventing the gas from blowing back and leaving that zonethrough the feed end. Operation with the apparatus illustrated in thedrawing and in the manner described in the following Example I, usingpre-neutralized detergent effectively avoids such blowback; in suchoperation the temperatures near the feed end of the intensive shearingzone are generally relatively low, usually lower than those near thedischarge end, so that the mixture adjacent the feed end is moreresistant to flow (e.g. more viscous). When the continuousneutralization procedure is used, blowback will occur at times,presumably due to the fact that the exothermic heat is usually generatedadjacent the feed end, raising the temperature there and making theingredients less viscous and less likely to form an airretaining plug.This effect can be prevented or reduced by suitable modifications tomake the configuration, dimensions, and temperature of the material atthe feed end such that its resistance to air flow is increased. Forexample, the circumferential edges of the feed screw flights can be madebroad and flat, rather than sharp, so as to increase the area of contactbetween the flight edges and the stationary internal Well of thehousing; other arrangements to seal the feed end more effectively may beused, e.g. in place of the open hopper 18 there may be an enclosed tubeof small diameter, having a feed screw operating therein, arranged at anangle (e.g. feeding downward at 90 to the shafts 12).

The following examples are given to illustrate this invention further:

EXAMPLE 1 Into the hopper of a device as illustrated in FIGS. 1 and 2,there was continuously fed 605 pounds per hour of a dry blend ofdetergent and builder salt (through the hopper 18) at room temperatureand 75 pounds per hour of cold water (through the port 21) containing aminor amount of a blue dye, while air was continuously injected into thelower portions of the resulting mixture at a pressure of 60 p.s.i.g.(measured just outside the ports 22 and 23, through which the air wassupplied). The dry blend contained 33.1% of sodium linear alkylbenzenesulfonate (the linear alkyl radicals having an average of 13carbon atoms and being about 15 mole percent C12, 55 mole percent C13and 30 mole percent C14, the alkyl substitucnt containing about 20% ofakyl groups whose benzene attachment is on the 2-carbon of the alkylgroup, the remainder of its alkyl groups having the benzene attachmenton the 3-, or higher, carbon atom), 12.3% tapioca flour, 32% sodiumbicarbonate, 22.4% pentasodium tripolyphosphate (commercial gradeanhydrous), together with minor amounts of perfume and impurities. Eachof the paired feed screw elements was composed of four helical turnsextending about 8 inches on the shafts, and the pattern of paddlesthereafter (using A to designate advancing paddles, as shown in FIGS. 7and 8, and N to designate the nonadvancing paddles) was 6A (meaning 6successive pairs of advancing paddles), 1N (meaning one pair ofnon-advancing paddles), 3A, 1N, 3A, 1N, 3A, 1N, 3A, SA. All the paddleswere arranged at 45 to the preceding and succeeding paddles, except forthe last five paddles, for which this angle was 90. The water injectionport 21 was at a point about 9 inches forward of the forward end of thefeed screw section, one air injection port 22 was at a point about 9inches forward of port 21, and the second air injection port was at apoint about 7 inches forward of port 22, and within the length of the 90five-paddle section. The dimensions of the paddles and the clearanceswere those described earlier in this specification. The discharge tube42 was rectangular, about 2 inches wide and about 1 inch high, and 6inches long; extended tube served as a zone for compacting the materialbeing extruded. The speed of rotation of the shafts was about 175 rpm.corresponding to about 9400 paddle cuts per minute. The residence timeof the material in the apparatus was less than minutes (the free volumeof the apparatus, per se, was about 0.4 cu. ft.). The material emergingfrom the discharge tube had a temperature of about 130 F. It retainedthe shape of the cross-section of the tube without significant slump,the thickness, width and shape of the extruded bar being substantiallythe same as the height, width, and shape of the extrusion opening. Afterit had been permitted to cool and harden, its density was about 1.25.

During the run there was no indication of leakage of air from theapparatus, either from its joints or from the feed end. Apparently theair was prevented from blowing back past the feed end by the presence ofthe pasty mass of material which was being advanced toward the dischargeend by the action of the feed screw elements and the advancing paddles.This pasty mass was at a lower temperature, and therefore was presumablymore resistant to flow (more viscous) than the more extensively workedmaterial nearer the discharge end of the apparatus.

By increasing the proportion of water (e.g. to about 100 lbs./hr.),products having a density of about 1.15, and even about 1.07, afterhardening at room temperature were obtained.

In this example (as in the following examples), hydration of thehydratable salts (e.g. the sodium tripolyphosphate) in the mixture waslargely incomplete during the mixing and extruding; the hydrationoccurring thereafter, on standing, contributed to the hardness of theproduct. This hydration appeared to take place substantially uniformlythroughout the cross-section of the bar; in penetrometer tests on a bar,made in a similar manner and aged one day at room temperature afterwrapping, the penetration measured at. the outer surface of the bar, was2.0 mm., which was the same as the penetration measured on a freshlyexposed surface about /3 inch from the outer surface of the day-old bar(the new surface being exposed by carefully cutting away a portion ofthe bar with a sharp razor blade, without compressing the surface). Thewarm material emerging from the extrusion nozzle could be deformedeasily, yielding readily to pressure with the fingers and was notsticky.

In these examples the material was subjected to intensive shearingforces in one portion of the apparatus and to lesser, but significant,shearing forces during its subsequent flow through the dischargeportions of the apparatus (said shearing forces accompanying the flow ofthe pasty material under pressure), and there was no stage during itstravel through the apparatus that the material was in a quiescent statein which it had an opportunity to set.

The extrusion pressures mechanically generated by the apparatus of theseexamples (i.e. the pressures generated when operating under the sameconditions but without injecting air into the apparatus) were relativelylow; for example, a pressure gauge connected to ports 22 and 23indicated a pressure of about 40-50 p.s.i.g. (when the air supply wasshut off).

The gas pockets, or pores, in the bars were microscopic and, under themicroscope, appeared to be discrete and unconnected; the bars were quitefree, throughout their thickness, of pores that were of such size as tobe visible to the naked eye.

The density of the freshly hardened bar was also substantially uniformthroughout its thickness.

The penetrometer measurements, previously mentioned, were made with astandard penetrometer needle (made from 0.41 inch diameter wire with thepoint ground and honed at an angle of 12) under a load of 151 grams, thereading being taken 15 seconds after application of the load.

EXAMPLE 2 In this example, the apparatus shown in FIGS. 1, 10 and 11 wasemployed. The dry material, fed into the hopper at the rate of about 776lb./hr., containing 12.3% sodium carbonate (commercial grade,anhydrous), 35.8% sodium sesquicarbonate (a hydrate), 31.1% pentasodiumtripolyphosphate (commercial grade, anhydrous), 17.1% tapioca flour,3.1% sodium toluene sulfonate, together with perfume and titaniumdioxide. Through port 19 (leading into lower portion of the sectioncontaining the feed screw flights) there was injected 294 lb./hr. of anacidic stream containing 96% of branched chain alkyl benzene sulfonicacid (the alkyl group having an average of 13 carbon atoms, derived fromlower polymers of propylene), 2% H 1% moisture and 1% by-prodnets andimpurities of the sulfonation reaction. Ports 21, 22 and 23 were locatedas in Example 1. Into port 21 (leading into the lower portion of thesection containing the paddles, near the feed end of the apparatus)there was injected 135 lb./hr. of water containing an indicator dye(Pylaklor Blue) which turns blue when the acid is neutralized. Air wasinjected into ports 22 and 23. The feed screw elements were arranged asin Example 1, but the paddle pattern was 5A, 1N, 3A, 1N, 4A, 1N, 3A, 1N,3A, 1N, 5A, all paddles being arranged at 45 to the preceding andsucceeding paddles. The material was continuously extruded as acontinuous slab of a width of about 9 /2 inches and a thickness of about1 /2 inch; the temperature of the slab as it was extruded was well overF. After cooling and hardening, the slab had a specific gravity of 1.39.It was cut into individual laundry bars and pressed in a conventionalsoap press.

EXAMPLE 3 In this example the apparatus used was similar to thatdescribed in Example 1 except that the sequence of paddles starting fromthe feed end was: 6A, 1N, 3A, 1N, 3A, 1N, 3A, 1N, 9A (the long axis ofeach paddle being offset, as in Example 1, 45 from the long axes of thepreceding and succeeding paddles, except that for the last five paddles,adjacent the discharge end, this angle of offset was 90). The dischargewas effected through a horizontal rectangular side discharge tube about2 inches wide, about 1 inch high and about 6 inches long, whose longaxis was at right angles to the axes of the shafts, which led from apoint on the lower portion of the housing adjacent the last few paddles,being situated on that side of the housing where the paddles had adownward movement. (The end wall of the apparatus in this case wasconstructed to block completely any discharge of material through saidend wall.)

A stream of dry-blended, screened (but not pulverized) solidingredients, of the following composition, was fed to the hopper at therate of 624 lbs./hr.:

All the salts were anhydrous.

The same detergent acid as used in Example 2 was fed at the same pointas in that example, at a rate of 415 lbs/hr.

A stream of cold water and a very small amount of blue dye was fed tothe port 21 at the rate of 70% lbs/hr.

Air under a pressure of about 65 p.s.i.g. was injected continuouslythrough the ports 22, 23.

No cooling water was employed in the jacket of the apparatus.

The bar emerging continuously from the discharge tube had a temperatureof about 186 F. It extruded smoothly, retaining the cross-section of theextrusion opening without significant slump, and was not sticky. Aftercooling, it was cut transversely to form individual bars.

The density of the bars was about 1.3.

Similar results were obtained when, instead of a discharge tube ofsubstantially uniform cross-section along its length, there was employeda discharge tube of the tapered, converging type, whose cross-section atits inlet end was larger than that of the extrusion opening.

The extruded material at this relatively high temperature of 186 F. wasfound to be considerably tougher than similar extrudates at lowertemperatures; it had sufiicient strength so that during the continuousextrusion, the hot bar (about 2 inches wide and about 1 inch in height)leaving the tube supported its own weight over a span, measuredhorizontally, of 4 feet or more forming a catenary curve whose lowestpoint was on the order of about 2 feet below the level of the two endsof that span.

EXAMPLE 4 Example 3 is repeated except that the stream of solids,supplied at the rate of 407 lb./hr., had the following composition:

52.1% of sodium sesquicarbonate (a hydrate) 29.5% of sodiumtripolyphosphate (commercial grade anhydrous) 16.2% tapioca starch plusT i and perfume.

The sulfonic acid stream is supplied to port 21 (rather than port 19) atthe rate of 117 lbs/hr. Instead of a simple water-color mixture, thereis supplied 76 lbs/hr. of a caustic-water-color stream containing 59%water and 40.9% of a 48.9% solution of NaOH in water; this is added atport 19 (rather than port 21).

14 EXAMPLE 5 In this example, the apparatus was like that of Example 3except that the paddle pattern was: 3A, 1N, 3A, IN, IA, 1N (after whichthe 1A, 1N sequence was repeated 11 times more). The stream of solidshad the following composition, all the ingredients being anhydrous:

Percent Soda ash 16.9 Sodium bicarbonate 40.7 Trisodium phosphate 5.8Sodium tripolyphosphate 28.6 Sodium sulfate 3.5 Carboxymethylcellulose.6- Sodium chloride .3 Lauric-myristic isopropanolamide 3.1 Q.S.perfume.

The detergent sulfonic acid stream was a branched chain alkyl benzenesulfonic acid, as in Example 2. The relative proportions of the threestreams (i.e., solidszacidzwater) were about 11:4:1, and the total rateof feed wa about 800 lbs/hr. Air was supplied through port 23 at apressure about 12 p.s.i. above the pressure mechanically generated bythe apparatus (i.e., the pressure generated when operating under thesame conditions but without air injection, which mechanically generatedpressure was on the order of about 25 p.s.i.g. in this example). Thematerial was discharged at a temperature of F. through the dischargetube which, in this case, was also externally heated by a small electricheater. The extruded bar had a density of about 1.4, had a content ofanionically active material (as determined by conventional titrationwith a cationic agent) of 25% and a moisture content of 10 /2%.

Using streams of the same composition and operating at a total feed rateof about 1000 lbs/hr. (with air at a pressure 2-3 p.s.i. above themechanically generated pressure) there was obtained a bar of density1.32 having a moisture content of 14%% and a content of anionicallyactive material of 22%.

The foregoing examples have dealt with processes in which a stream ofair was injected. The air may also be introduced in other forms; forexample, spray-dried hollow particles, or beads, of well knownstructure, of the pre-neutralized detergent (i.e. alkyl benzenesulfonate, which may be blended with sodium silicate as in US. Patent2,515,577 of July 18, 1950) may be used as the detergent feed materialunder conditions such that the air contained within these particles(e.g., air encapsulated in the particles) is in large part retainedwithin the mass of material being blended; by operating in this manner,without injection of a stream of air, using substantially the sameprocedure and basic formulation as described in Example 1, and employingspray-dried hollow particles as the detergent feedstock, bars of density1.35-1.4 have been produced.

Typically, a cross section of the bar (such as a surface exposed bycareful slicing) appears, under the microscope, as a relatively looseaggregation of materials including builder salt crystals and starchgrains (when starch is used as a component) with numerous discretespaces or interstices distributed throughout the mass, some of theinterstices being as small as the starch grains (10-15 microns indiameter) and others, less numerous, being considerably larger (e.g., 20times the diameter of the starch grains). The largest crystals are onthe order of 200-300 microns long and about 2050 microns wide, and thereare numerous crystals of much smaller size.

Although the present invention has been described with reference toparticular embodiments and examples, it will be apparent to thoseskilled in the art that variations and modifications can be substitutedtherefor without departing from the principles and true spirit of theinvention.

What is claimed is:

1. Process for the production of detergent laundry bars which comprisescontinuously feeding finely divided solid water-soluble inorganichydratable builder salt to a zone in which there is formed a mixture ofsaid salt, a synthetic anionic detergent, starch, and Water and in whichthe ingredients of said mixture are continuously intensively shearedtogether to form a heated flowable blend and continuously. forwardedthrough said zone, continuously dispersing gas into the material beingintensively sheared, and continuously discharging an intimate plasticblend of said detergent, said dispersed gas, said starch and saidbuilder salt from said zone, said process including the steps ofextruding said heated flowable blend through a heated extrusion openingof such size that said blend is extruded continuously from saidextrusion opening as a mass whose cross-section has a thickness of atleast about inch and an area of at least about 2 square inches, saidflowable blend being maintained continuously in a flowable condition andcontinuously under shearing forces from the time of the formation ofsaid blend until its passage through said extrusion opening, hardeningsaid extruded mass and subdividing said mass into detergent laundrybars, said detergent being a synthetic anionic sulfonate salt detergentand being formed in said zone by the exothermic reaction of a basicneutralizing agent with the corresponding detergent sulfonic acid inliquid state in the presence of solid pentasodium tripoly' phosphatebuilder salt supplied to said zone in finely divided substantiallyunhydrated form, the process being one in which the extruded blendcontains partially hydrated water soluble inorganic builder saltsincluding partially hydrated pentasodium tripolyphosphate and in whichhydration of said salts occurs during, and contributes to, the hardeningof said extruded mass, said gas being selected from the group consistingof air, CO and N the proportions of the ingredients, based on the weightof the finished mixture being in the ranges of about 10 to 40% of thesynthetic anionic detergent, about 45 to 85% of the builder salt, about10-12% of starch, and about 2 to 30% of water.

2. Process as set forth in claim 1 in which the material leaves saidextrusion opening within 2 minutes of leaving the intensive shearingzone and in which the heated extrusion opening is maintained at atemperature of about 10 to F. above the temperature of the extrudedmass.

3. Process as set forth in claim 1 in which said extrusion takes placeunder a mechanically applied pressure below about 100 p.s.i.g.

4. Process as set forth in claim 3 in which said gas is air, the airbeing injected at a pressure of up to about 100 p.s.i.g.

5. Process as set forth in claim 4 in which the air pressure is about 20to 100 p.s.i.g.

6. Process as set forth in claim 1 in which the material leaves saidextrusion opening within about one minute of leaving the intensiveshearing zone and in which said extrusion takes place under amechanically applied pressure below about 60 p.s.i.g.

7. Process as set forth in claim 1 in which said neutralizing agent isselected from the group consisting of sodium and potassium carbonate,oxide and hydroxide.

8. Process as set forth in claim 1 in which said detergent acid is ahigher alkyl benzene sulfonic acid and said finely divided builder saltcomprises sodium carbonate, at least a portion of said sodium carbonateacting as a neutralizing agent by reacting with said acid.

9. Process as set forth in claim 7 in which said detergent acid is ahigher alkyl benzene sulfonic acid and said neutralizing agent is sodiumhydroxide, said sodium hydroxide being supplied in aqueous solution tosaid zone.

10. Process as in claim 1 in which said zone is an enclosed space intoone end of which the ingredients of the mixture are fed and from theother end of which the resulting heated flowable blend containingdispersed gas is extruded through an extrusion opening as a mass whosecross-section has a thickness of at least about inch and an area of atleast about 2 square inches, said fiowable blend being maintainedcontinuously in a flowable condition and continuously under shearingforces from the time of the formation of said blend until its passagethrough said extrusion opening, said extruded mass is then hardened andsubdivided into detergent laundry bars, said process including the stepsof injecting air into said zone at a superatmospheric pressure greaterthan the pressure mechanically generated in said zone, whilesubstantially preventing the escape of air from the feed end of saidzone by forming, of the materials being fed to said zone, a plug capableof retaining the air injected into said zone, said extruded masscontaining finely divided partially hydrated builder salt includingpentasodium tripolyphosphate, the hydration of said builder saltoccurring during, and contributing to, the hardening of said extrudedmass, the proportions of the ingredients fed to said zone being suchthat the bars contain about 10- synthetic anionic detergent, about to ofa mixture of sodium tripolyphosphate and sodium bicarbonate or sodiumsesquicarbonate, about 10-20% of starch, and about 4 to 25% water, thetotal residence time in said zone, from the initial contact of the solidbuilder salt and the liquid in said zone to the extrusion of the blendthrough said extrusion opening, being below 10 minutes, said bars havinga density of about 1.3 to 1.4, having gas pockets distributedtherethrough, and containing crystals of hydrated pentasodiumtripolyphosphate.

11. Process as in claim 10 in which the sulfonate detergent is sodiumalkylbenzenesulfonate having about 13 carbons in the alkyl, saidsulfonate detergent is present in amount of above 15 to 30% in saidbars, said basic neutralizing agent is sodium hydroxide or sodiumcarbonate, and the air is injected at a pressure of about 20 top.s.i.g., the gas pockets in the bars are microscopic and distributedsubstantially throughout said bars, and said bars consist essentially ofsaid sulfonate detergent, said builder salt, said starch, and water.

References Cited UNITED STATES PATENTS 2,407,647 9/ 1946 Bodman 252--1213,178,370 4/1965 Okenfuss 252-438 3,081,267 3/1963 Laskey 252 3,089,1975/1963 Chaffee et al. 264--50 FOREIGN PATENTS 858,075 1/ 1961 GreatBritain.

OTHER REFERENCES Synthetic Detergents-McCutcheon-MacNair-Dorland Co.,N.Y., 1950, p. 187498.

Soaps and Detergents-Thomssem, MacNair-Dorland Co., N.Y., 1949, p. -188.

LEON D. ROSDOL, Primary Examiner P. E. WILLIS, Assistant Examiner US.Cl. X.R. 252161; 264-50

